This application claims the benefit of U.S. Provisional Application Ser. No. 60/294,391, filed May 29, 2001.
The present invention relates to measurements of electrical activity in a body. More particularly, the invention relates to measurement and analysis of the measurements to predict the condition of a portion of a body.
Presently there is no objective manner with which to evaluate the contractility of the uterus. This is true either in non-pregnant patients where hypercontractility is associated with dysmenorrhea or in pregnant patients where the uterus is sometimes active prior to term. Normally the uterus is quiescent in non-pregnant women and during most of pregnancy. However, at the end of pregnancy, the myometrium undergoes a series of changes that lead to synchronous, rhythmic uterine contractions (labor). The diagnosis of labor is the most significant problem faced by obstetricians. In addition, pre-term labor, which occurs in about 10% of pregnant patients, is difficult to diagnose. Frequently, term or pre-term labor requires adjuvant therapy to either stimulate or inhibit contractility of the uterus.
Since there is some minor spontaneous uterine activity at all times during pregnancy, it is often not possible to distinguish between this physiological activity at term or preterm labor. The state of the cervix is commonly used as a predictor of labor. However, the dilatation of the cervix usually occurs relatively late, during actual labor. In addition, labor and changes in the cervix can occur independently. Alternatively the frequency of contractions is used to diagnose labor, sometimes recorded with a tocodynamometer. However, these methods give only crude subjective estimates of uterine contractility.
The uterus does not contract vigorously throughout most of pregnancy and this provides a tranquil environment for the growing fetus. At term, the uterus normally begins to contract forcefully in a phasic manner (labor) to expel the fetus. Contractions of the uterus are directly proportional to the underlying electrical activity of the muscle. The frequency, duration, and magnitude of a uterine contraction are directly proportional, respectively, to frequency of bursts of action potentials, and the propagation (also referred to as conduction) of action potentials over the uterus and the recruitment of muscle cells. A similar situation exists in heart muscle, although heart and uterine muscle are different with respect to structure and configuration of the action potentials. The action potentials are accompanied by the influx of calcium into the muscle cells to activate the contractile apparatus.
Thus, by recording uterine electrical activity one can assess the contractility of the myometrium. Similar technology is used to record cardiac electrical activity to determine the normal or abnormal function of the heart.
Many studies have previously recorded myometrial electrical activity using electromyography (EMG) where electrodes are placed directly on the uterus. These studies show that the myometrium generates little electrical activity prior to labor but activity increases tremendously during labor reflecting the mechanical events. Studies of interest are demonstrated in publications by Csapo, Chapter 43, xe2x80x9cForce of Labor,xe2x80x9d Principles and Practice of Obstetrics and Perinatology, Ed. L. Iffy and H. A. Kaminetzky, John Wiley and Sons Publishing 761-799, 1981; Garfield et al., xe2x80x9cControl of Myometrial Contractility: Role and Regulation of Gap Junctions,xe2x80x9d Oxford Rev. Reprod. Biol. 10:436-490, 1988; Wolfs and Van Leeuwen, xe2x80x9cElectromyography observations on the human uterus during labor,xe2x80x9d Acta Obstet. Gynecol. Scand. [Suppl.] 90:1-62, 1979; and more recently by Devedeux et al., xe2x80x9cUterine Electromyography: A Critical Review,xe2x80x9d Am J. Obstet. Gynecol. 169:1636-1653, 1993. One may measure and use uterine EMG activity by direct contact with the uterus to predict normal and abnormal uterine contractions. However, it is not practical to place electrodes directly on the uterus. To do this under the present level of understanding one must surgically implant electrodes on the uterine surface or introduce a catheter electrode through the vaginal canal and puncture the fetal membranes.
It would be desirable to record uterine EMG activity from the abdominal, cervical or vaginal surface. Previous studies of electrical activity of the uterus recorded with electrodes placed on the abdominal surface failed to record bursts of action potentials from the uterus and generally showed no association of uterine electrical activity with contractility. Studies of interest are included in the above-noted publications by Wolfs and Van Leeuwea and by Devedeux et al. Wolfs and Van Leeuwea summarized all studies prior to 1979 and concluded, xe2x80x9cit has never been clearly shown that the potential fluctuations obtained by means of electrodes attached to the abdominal wall, do indeed represent the electrical activity of the uterus.xe2x80x9d (Page 7.) Similarly, Devedeux et al state that abdominal monitoring of uterine electrical activity xe2x80x9crequires further investigationxe2x80x9d (Page 1649).
Recently, studies have been done which establish that there is significant correlation between the potentials of the uterus as measured at the abdominal surface and directly at the uterus. These studies show that such electrical signals can be quantified by mathematical means, for example, with Fourier analysis or Wavelet analysis: Garfield, R E, et al, xe2x80x9cControl and assessment of the uterus and cervix during pregnancy and labour, 1996xe2x80x9d; Buhimschi C, Garfield R E. xe2x80x9cUterine activity during pregnancy and labor assessed by simultaneous recordings from the myometrium and abdominal surface in the rat,xe2x80x9d Am. J. Obstet Gynecol 1998, 178:811-22; and Garfield R E, et al, xe2x80x9cInstrumentation for the diagnosis of term and preterm labour,xe2x80x9d J. Perinat Med 1998; 26; 413-436.
Part of the difficulty in interpretation of electrical activity recorded from the uterus lies in the fact many investigators, including Wolfs and Van Leeuwea and Devedeux et al., have failed to recognize that action potentials drive the uterus to contract. Action potentials are not responsible for contraction of some smooth muscle tissues such as airway muscle and some vascular muscles, and therefore many researchers confound the uterus with other smooth muscles. Thus, many of these studies have attempted to correlate electrical activity with mechanical contractions in order to show that electrical activity is or is not responsible for contractions. It is now clear (from publications by Marshall, xe2x80x9cRegulation of Activity in Uterine Smooth Muscle,xe2x80x9d Physiol. Rev. 42-212-227, 1962; Csapo, Chapter 43. xe2x80x9cForce of Labor,xe2x80x9d Principles and Practice of Obstetrics and Perinatology, Ed. by I. Iffy and H. A. Kaminetsky, John Wiley and Sons Publishing, 761-799, 1981; Garfield et al., xe2x80x9cControl of Myometrial Contractility: Role and Regulation of Gap Junctions,xe2x80x9d Oxford Rev. Reprod. Biol. 10:436-490, 1988; and Garfield, Chapter 3 xe2x80x9cRole of cell-to-cell Coupling in Control of Myometrial Contractility and Labor,xe2x80x9d Control of Uterine Contractility, Ed. R. E. Garfield and T. Tabb, CRC Press. 39-81. 1994) that action potentials activate the uterus to contract and that by measuring uterine electrical activity one can indirectly estimate contractility.
There has been much progress in monitoring adult ECG using an array of surface electrodes placed on the skin (Interventional Electrophysiology, 2nd Edition, Ed. by Singer. Lippincott Williams and Wilkins, April 2002). There has also been some success in monitoring maternal and fetal cardiac activity from the abdominal surface of pregnant patients using electrodes (Kanjilal, et. al., xe2x80x9cFetal ECG Extraction from Single-Channel Maternal ECG Using Singular Value Decomposition,xe2x80x9d IEEE Trans Biomed Eng. January; 44(1): 51-9, 1997; Kwon, et. al., xe2x80x9cAbdominal Fetal EKG Noise Removal,xe2x80x9d Biomed Sci Instrum. 32: 87-92, 1996). However, the devices and methods of data acquisition and signal processing delineated in these studies seem inadequate for proper patient evaluation and diagnosis.
In trans-abdominal recording of uterine EMG, maternal and fetal ECG, and fetal EEG, background noise due to respiration, patient movement and skin potentials is very high in about 15% of the records. What is needed is a system that is effective in non-invasively recording, identifying, and analyzing uterine EMG and/or maternal and/or fetal cardiac or fetal brain signals, simultaneously or separately, while reducing the effects due to background noise, in more than 95% of all pregnant patients.
The present invention presents a method and apparatus for recording and analyzing uterine electrical activity from the surface of the abdomen, vagina, or cervix for the purpose of diagnosing contractile patterns of the uterus in pregnant and non-pregnant patients, as well as monitor maternal and fetal ECG and fetal brain activity. The present invention provides data analysis techniques for analyzing the electrical data measured from the surface of a patient to characterize uterine, abdominal, and cardiac muscle activity of the patient, as well as cardiac and brain activity of the fetus simultaneously or separately.
The signals will be amplified and analog filtered for background noise. Possible filtering setups are to band-pass filter from about 0.001 Hz to about 3.000 Hz for uterine EMG or to filter from about 0.5 Hz to about 100 Hz for fetal EEG or to filter from about 1 Hz to about 5 Hz for fetal heart rate. Other filtering schemes can be used when certain uterine EMG and maternal fetal biophysical signal frequencies need to be isolated.
Additional filtering of background noise will be done by cross-correlation, auto-correlation, adaptive filtering, matched filtering, and/or singular value decomposition or other multi-channel methods, where common components of noise from any or all of the potentials recorded are reduced or removed, leaving the desired uterine EMG, maternal cardiac, and fetal brain electrical signals. The unit will have the capability of determining and/or modifying or maintaining phase relationships between various channel combinations in order to carry out such noise-reduction utilizing these methods.
In particular, the present invention contemplates a method of analyzing surface electrical data to characterize maternal uterine, maternal abdominal, maternal and fetal cardiac, and/or fetal brain activity, comprising applying a multi-polar arrangement of action potential-, or electrical signal-measuring electrodes to an abdominal, vaginal, or cervical surface of a patient; measuring electrical signals produced at the electrodes; analyzing frequency components of the electrical signals; and characterizing uterine, abdominal, cardiac or fetal brain activity of the patient based on the analysis of frequency components or other signal quantities. Ideally, the analysis of uterine activity indicating parameters is performed for data from at least three (3) bursts of action potentials within the stored electromyographic signals, and at least 30 minutes of recording for the electrical signals generally. The uterine burst analysis, or cardiac or brain signal analysis may include determining the frequency, duration, amplitude, number of action potentials per burst, activity per unit time of interest, and power density spectrum of at least three (3) bursts of action potentials and the frequency, duration, and amplitude of a plurality of action potentials or use of integration of signals, 3-dimensional mesh plots, vector analysis, wavelet transforms, power spectrum, Fourier transforms, spectral-temporal mapping, complexity, chaos, fractals, zero-crossings, randomness, non-linearity, likelihood ratios, and statistical methods, Wigner-Ville or Heisenberg-Gabor analysis (as would be known to those with ordinary skill in the art), or other joint time-frequency analysis for one or more of the uterine, cardiac, or brain signals. As a further embodiment, the method also includes predicting treatment for the patient based on the characterization of uterine, cardiac or fetal brain activity, in particular this treatment may be pharmacologically inducing or inhibiting labor in the patient.
The burst of action potentials may be analyzed using wavelet or Cepstrum Analysis, as described in Akay, Chapter 6, xe2x80x9cCepstrum Analysis,xe2x80x9d Biomedical Signal Processing, Academic Press (1994). The uterine, cardiac, and fetal brain signals may also be analyzed using non-linear dynamics, or chaotic analysis, as described in Molnar, et al., xe2x80x9cCorrelation Dimension of Changes Accompanying the Occurrence of the Mismatch Negativity and the P3 Eventxe2x80x94Related Potential Component,xe2x80x9d Electroencephalography and Clinical Neurophysiology, 95 (1995), pp. 118-26; Elbert, et al., xe2x80x9cChaos and Physiology: Deterministic Chaos in Excitable Cell Assemblies,xe2x80x9d Physiology Reviews, Vol. 74, No. 1, Jan. 19, 1994; and Skinner, et al. xe2x80x9cThe Point Correlation Dimension Performance with Non-Stationary Surrogate Data and Noise,xe2x80x9d Integrative Physiological and Behavior Science, Vol. 28, No. 3, pp. 217-34 (September 1994). The uterine, cardiac, and fetal brain signals may also be analyzed using indices, comprising power density spectrum and frequency data. The distribution of intervals between successive action potentials may be characterized as an indicator of aberrant activity.
The invention also contemplates the stimulation of the vagina of the patient while the uterine electromyographic and maternal and fetal cardiac and fetal brain electrical signals are being stored. This stimulation permits the assessment from the stored electrical signals for the phenomenon of conduction, and permits the diagnosis of labor as a function of the signals, as well as an evaluation of maternal and fetal well-being based on cardiac and brain signals. The stimulation of the vagina may either be electrical, mechanical or pharmacological, for example through the infusion of oxytocin to the patient.
Other further embodiments contemplate isolating high frequency uterine electrical components within the electromyographic signals; isolating a fast wave component within the high frequency components; determining a low-frequency domain, including low-frequency components within the fast wave component, and a high-frequency domain, including high-frequency components within the fast wave component; and determining a relationship between the low-frequency domain and the high-frequency domain indicative of an obstetrical diagnosis. This relationship can be indicative of pre-term or term uterine activity.
Other embodiments of the present invention contemplate analyzing the uterine, cardiac, and fetal brain electrical frequency ranges of interest using wavelet analysis methods to de-correlate the signals, displaying the signal components by sub-band, and comparing the energy levels contained in particular sub-bands versus time of pregnancy. The wavelet transform or wavelet packet analysis may be used to generate various measures (such as amplitudes and ratios) of the wavelet maxima, skeleton, or energy content within particular sub-bands. The resulting decomposition(s) of the signal may be used in de-noising by thresholding, wavelet shrinkage, and comparable approaches. The signals may be compressed with high efficiency before storage by discarding the smallest wavelet coefficients.
An alternative embodiment of the present invention contemplates a method of analyzing transabdominal/transvaginal/transcervical uterine data to characterize the activity in the tissue, comprising applying an arrangement of multiple (tri-polar, quadra-polar, or other multi-polar configuration) action potential-, or electrical signal-measuring electrodes to a surface of a patient; measuring uterine, cardiac, and fetal brain signals picked up by the electrodes; analyzing the signals; determining potential vector characteristics of the signals to identify direction and rate of propagation of uterine electrical activity; and characterizing uterine activity based on the potential vector characteristics. This potential vector can be indicative of an obstetrical diagnosis, including pre-term or abnormal term uterine activity.
The apparatus of the present invention works in real-time and includes at least three electrodes (tri-polar, quadra-polar, etc. configurations) that are applicable to the abdominal, cervical or vaginal surface of the patient under analysis; differential analog filters/amplifiers electrically coupled to the electrodes and approved for human use, to receive and amplify a signal indicative of action potentials measured by the electrodes; an analog filtering device capable of segregating and identifying uterine, maternal and fetal cardiac, and fetal brain electrical signals, including action potentials, in pre-selected frequency ranges; an analog-to-digital converter, possibly incorporated into a digitizer, that is electrically coupled to receive an analog input from the amplifier indicative of action potentials, or electrical signals, measured by the electrodes, and that converts these electrical signals picked up by the electrodes into digitized data which are indicative of uterine, maternal and fetal cardiac, and fetal brain electrical signals; a program or hardware for combining multiple potentials or summing or performing various mathematical pre-processing of signals to yield the desired number and type of differential signals, each of which corresponds to a xe2x80x9cchannelxe2x80x9d of the data acquisition system; a process for further reducing noise components common to one or more channels of data by utilizing a multi-channel process for noise elimination, such as auto-correlation, cross-correlation, adaptive filtering, matched filtering, and/or singular value decomposition, or any other such techniques; the capability of determining and/or modifying or maintaining phase relationships between various channel combinations in order to carry out such noise-reduction utilizing such methods; a memory for storing the digitized signals, and comprising sufficient storage capacity to store data resulting from a sampling of electromyographic signals at a sampling frequency of at least 100 Hz. for a duration of time sufficient to record on all channels for at least three (3) bursts of action potentials or 30 minutes, whichever is longer; and a programmed computer. The computer comprises an expert system programmed to generate and/or analyze the frequency, duration, amplitude, power density spectrum, integration of signals, 3-dimensional mesh plots, vector analysis, wavelet transforms, power spectrum, Fourier transforms, spectral-temporal mapping, complexity, chaos, fractals, zero-crossings, randomness, non-linearity, likelihood ratios, and statistical methods of the action potential bursts, trains, or groups, as well as individual action potentials of uterine, cardiac and fetal brain activity. The expert system is further capable of characterizing uterine, cardiac and fetal brain activity and of identifying abdominal muscle contractions, based upon this analysis or other analyses.
The expert system may comprise algorithms needed to perform a Cepstrum analysis, wavelet analysis, chaotic analysis, or myometrial analysis of the action potentials. The expert system may also be capable of identifying abdominal muscle contraction, and/or identifying and analyzing QRS complexes and heart-rate in maternal and fetal cardiac activity, determining alpha, beta, theta, and delta brain waves and their morphologies from the fetal brain electrical signals. The expert system may also be capable of evaluating the trend of uterine activity over the course of labor, encompassing many hours, to determine whether labor is progressing, and alerting the physician to the possible diagnosis of failure-to-progress and the need to treat by pharmacological, surgical, or electrical means. The expert system may be capable of assessing other clinical data in combination with the EMG data, such as the normality or abnormality of the maternal and fetal heart activity and fetal brain activity.
An alternative embodiment contemplated by the present invention is an apparatus for recording and analyzing uterine, cardiac, and fetal brain electrical activity from the abdominal surface, comprising at least three (3) action potential-measuring electrodes for recording electrical signals applicable to an abdominal surface of a patient under analysis; an analog-to-digital converter, connected to at least three electrodes, for converting electrical signals produced by the electrodes into digitized data indicative of the electrical signals; a memory for storing the digitized signals; and a programmed computer for analyzing frequency components of the stored digitized electrical signals, and for providing an indication of uterine, cardiac, and fetal brain electrical activity from the patient and the fetus under analysis as a function of the stored digitized signals. A still further embodiment contemplates an apparatus wherein the programmed computer is used further for determining power density spectral characteristics of the frequency components of the electrical signals.
The present invention further contemplates an apparatus in the form of a remote uterine monitoring system for analyzing surface electrical data to characterize uterine activity, maternal and fetal cardiac and fetal brain activity, comprising a remote uterine monitor and a central programmed computer in communication with the remote uterine monitor for analyzing stored digitized electrical signals, and for providing an indication of uterine, maternal and fetal cardiac, and fetal brain electrical activity from the patient and the fetus under analysis as a function of the stored digitized signals. The remote uterine monitor includes an arrangement of at least three (tri-polar, or quadra-polar, etc. configurations) action potential-, or electrical signal-measuring electrodes applicable to an abdominal surface of a patient under analysis; and a remote analog-to-digital converter, connected to the at least three electrodes, for converting electrical signals picked up by the electrodes into digitized data indicative of the uterine, maternal and fetal cardiac and fetal brain signals.
In a further embodiment, the remote uterine, cardiac, and fetal brain monitor and the central programmed computer communicate on-line through a telephone line or through wireless communication, such as digital or cellular phones or over radio or television frequencies, for example. In a still further embodiment, the remote uterine monitoring system also includes remote signal processing, analysis, and storage for recording the digitized electrical signal data, and wherein the central programmed computer communicates with the remote uterine monitor off-line through the remote storage device (for example, through Bluetooth or similar technology). In a still further embodiment, the remote uterine monitoring system communicates to pagers and/or cell-phones directly on the person of the doctors or hospital staff involved in treating/monitoring the patient and the fetus in question, or to family members of the patient in question, etc.
A method is provided for characterizing uterine electrical activity, comprising applying an action potential measuring multi-polar arrangement of electrodes to an abdominal, vaginal or cervical surface of a patient; isolating a system from the patient for analog filtering and amplifying an electrical signal as appropriate to isolate desired frequency components of said signal from background noise in said signal; acquiring analog electrical uterine, maternal or fetal cardiac signals, fetal brain signals, or a combination thereof transmitted through said electrodes at a sampling frequency between about 0.5 and 1 kHz for a duration of time sufficient to record at least 3 bursts of action electrical potentials from said signals; removing unwanted signal components through a multi-channel noise elimination scheme; storing said acquired signals; using detection algorithms to detect one or more attributes of said uterine, maternal or fetal cardiac activity, fetal brain activity, or combination thereof that are present in said acquired signals; analyzing at least a portion of said activity, indicating parameters from at least one burst of the action potentials within the stored signals; characterizing said activity from said patient based on said parameter analysis; determining electrically when contractions occur and plotting the contractions; simulating data output of a tocodynamometer or an intra-uterine pressure catheter; and predicting when a patient will go into labor or delivery, or a combination thereof.
Further, a system is provided for recording and analyzing uterine electrical activity for the abdominal, cervical or vaginal surface, comprising: an arrangement of at least three electrodes forming a multi-polar arrangement adapted to measure electrical signals due to action potentials emitted from an abdominal, vaginal, or cervical surface of a patient under analysis to establish uterine, maternal and fetal cardiac, and fetal brain signals and each electrode further adapted to conduct an analog signal indicative of said action potentials, each electrode-pair being identified with one channel of data; at least one analog filter adapted to remove unwanted signal components from the uterine, maternal and fetal cardiac, and fetal brain signals; at least one differential, isolated, analog amplifier electrically coupled to said electrodes to receive and amplify signals indicative of said action potentials measured by said electrodes; at least one analog to digital converter adapted to generate digital signals from the analog signals produced by the amplifiers; at least one memory comprising sufficient storage capacity to store data resulting from a sampling of electrical signals at a sampling frequency of at least 100 Hz from a single patient for at least 1 hour, said memory adapted to receive a digital input from said analog to digital converter; a computer programmed to import electrical signal data from multiple channels, or multiple differential signals from multiple electrode-pairs, formed from an array of said multi-polar arrangement of electrodes, and to perform mathematical functions on at least two of the potentials measured to generate multiple channels of data which are the result of at least one mathematical combination of said potentials from said mathematical functions; said computer programmed to perform multi-channel filtering on at least one of the channels of data to remove unwanted noise components common to one or more channels; said computer programmed to analyze frequency, duration, amplitude, power density spectrum, wavelet transforms, Fourier transforms, rate of rise and fall of signals, spectral-temporal mapping, complexity, chaos, fractals, zero-crossings, randomness, non-linearity, likelihood ratios, statistical evaluations, Wigner-Ville or Heisenberg-Gabor analysis, or other joint time-frequency analysis on the uterine, cardiac, and brain signals acquired, said computer further being adapted to characterize uterine, maternal and fetal cardiac, and fetal brain activity based upon said analysis. Further, the system can be used to plot contractions, plot contraction strength, assess maternal and fetal heart activity, and fetal brain activity, and accurately predict labor and delivery, without the need for using a tocodynamometer or an intra-uterine pressure catheter, or other such typical devices.
In another embodiment, a remote uterine monitoring system is provided for remotely characterizing uterine activity, comprising: at least three electrodes forming a multi-polar arrangement adapted to measure electrical signals of action potentials emitted from an abdominal, vaginal, or cervical surface of a patient under analysis and further adapted to emit an analog signal indicative of action potentials measured by said electrodes; an isolation system comprising analog filters adapted to remove unwanted signal components from the uterine, maternal and fetal cardiac, and fetal brain signals; at least one analog differential amplifier coupled to said electrodes, isolated from the patient by said isolation system, and adapted to receive and amplify signals indicative of action potentials measured by said electrodes; a computer programmed to import electrical signal data from multiple channels, or multiple differential signals from multiple electrode-pairs, formed from an array of said multi-polar arrangement of electrodes, and to perform mathematical functions on two or more of the channels to generate channels of data, which are the result of such mathematical combination of said potentials; said computer adapted to perform multi-channel filtering on said channels of data to remove unwanted noise components common to one or more channels; said computer programmed to analyze the frequency, duration, amplitude, power density spectrum, wavelet transforms, Fourier transforms, rate of rise and fall of signals, spectral-temporal mapping, complexity, chaos, fractals, zero-crossings, randomness, non-linearity, likelihood ratios, statistical evaluations, Wigner-Ville or Heisenberg-Gabor analysis, or other joint time-frequency analysis on the uterine, cardiac, and brain signals acquired, said expert system further being adapted to characterize maternal uterine, maternal and fetal cardiac, and fetal brain activity based upon said analysis; at least one data transmission system, coupled to said computer, adapted to transmit uterine, maternal and fetal cardiac, and fetal brain signals, processed or unprocessed, to a remote location from said computer via a telecommunications link; at least one remote analog to digital converter coupled to said data transmission system to receive an analog input from said amplifier indicative of action potentials measured by said electrodes; at least one memory comprising sufficient storage capacity to store data resulting from a sampling of trans-abdominal, trans-vaginal, trans-cervical electrical signals, or a combination thereof, at a sampling frequency of at least 100 Hz from a single patient for at least 1 hour, said memory adapted to receive a digital input from said analog to digital converter indicative of action potential signals received by said converter; at least one receiver adapted to collect the uterine, cardiac, or brain data, processed or unprocessed, which is transmitted from said computer at the site of the patient; and at least one remote computer located remote from the patient and coupled to said receiver to import received data from the site of the patient and programmed to analyze the frequency, duration, amplitude, power density spectrum, wavelet transforms, Fourier transforms, rate of rise and fall of signals, spectral-temporal mapping, complexity, chaos, fractals, zero-crossings, randomness, non-linearity, likelihood ratios, statistical evaluations, Wigner-Ville or Heisenberg-Gabor analysis, or other joint time-frequency analysis on the uterine, cardiac, and brain signals acquired, said remote computer further being capable of characterizing maternal uterine, maternal and fetal cardiac, and fetal brain activity based upon said analysis.
These and other features and advantages of the present invention will become apparent to those of ordinary skill in this technology with reference to the following detailed description and appended drawings.